Various components of transmission assemblies such as, for example, impeller assemblies and turbine assemblies are subject to significant forces from transmission fluid flowing throughout transmission housing. The impeller assembly includes a plurality of impeller blades affixed to an impeller assembly. The blades extend radially and are circumferentially spaced around the entire housing. Adequate mechanical attachment of the impeller blades to the impeller assembly has not been achieved. Therefore, the impeller blades have been attached to the impeller assembly by way of a coating process known as brazing. Likewise, the turbine blades have also been attached to the turbine housing by brazing in a similar manner.
Brazing is achieved by applying alloys to the joints formed between the blades and the housing and raising the temperature of the assembly to the melting temperature of the alloy. Additionally, brazing is also known to cause a rough surface resulting in oil turbulence in the impeller and turbine assemblies, which adversely affects efficiency and performance. While the brazing process has generally proven acceptable to secure the blades to the housings, a number of drawbacks make it desirable to eliminate brazing by way of a more secure mechanical attachment.
For example, the alloy used to braze the joints described above cause significant environmental hazards requiring significant measures be taken to avoid a detriment to technician health and contamination to the environment at large. Furthermore, the temperatures at which the assemblies must be raised to melt the brazing material is known to significantly weaken the metallic structure of both the housing and the blades. Furthermore, the addition of brazing material to the assemblies increases the mass of these assemblies significantly, which reduces the efficiency of the transmission and the associated vehicle.
Therefore, it would be desirable to eliminate the addition of brazing material to the impeller and turbine assemblies of a transmission by way of providing a more secure mechanical attachment of these blades to their housing.